龍卷風是(shi)一種(zhong)少見的(de)(de)局地性(xing)、小(xiao)尺(chi)度、突發性(xing)的(de)(de)強(qiang)對(dui)流天氣,是(shi)在(zai)強(qiang)烈的(de)(de)不穩定的(de)(de)天氣狀(zhuang)況下由空氣對(dui)流運(yun)動造成的(de)(de)、強(qiang)烈的(de)(de)、小(xiao)范圍的(de)(de)空氣渦(wo)旋(xuan)。
從(cong)積雨云(yun)中伸下(xia)的(de)猛烈旋(xuan)轉的(de)漏斗狀(zhuang)云(yun)樓。它有(you)時(shi)稍伸即隱,有(you)時(shi)懸掛空中或觸及地(di)(di)面(mian)(mian)。龍(long)(long)(long)卷(juan)(juan)(juan)(juan)風(feng)(feng)(feng)漏斗云(yun)的(de)軸(zhou)一(yi)般垂直(zhi)于地(di)(di)面(mian)(mian),在發展的(de)后期(qi),當(dang)上下(xia)層(ceng)風(feng)(feng)(feng)速(su)相差較大(da)時(shi),可(ke)(ke)成傾斜狀(zhuang)或彎(wan)曲狀(zhuang)。其(qi)(qi)下(xia)部直(zhi)徑(jing)最(zui)(zui)小(xiao)的(de)只(zhi)有(you)幾米,一(yi)般為(wei)數百米,最(zui)(zui)大(da)可(ke)(ke)達(da)(da)千(qian)(qian)米以上,上部直(zhi)徑(jing)一(yi)般為(wei)數千(qian)(qian)米,最(zui)(zui)大(da)可(ke)(ke)達(da)(da)10公(gong)(gong)(gong)里(li)(li)。龍(long)(long)(long)卷(juan)(juan)(juan)(juan)風(feng)(feng)(feng)的(de)尺度很(hen)(hen)(hen)小(xiao),中心(xin)氣(qi)壓(ya)很(hen)(hen)(hen)低(di)(di),造(zao)(zao)成很(hen)(hen)(hen)大(da)的(de)水(shui)(shui)平氣(qi)壓(ya)梯度,從(cong)而導致強烈的(de)風(feng)(feng)(feng)速(su),中心(xin)風(feng)(feng)(feng)速(su)可(ke)(ke)達(da)(da)100-200米/秒。由于氣(qi)流(liu)的(de)旋(xuan)轉力(li)很(hen)(hen)(hen)強,常(chang)將地(di)(di)面(mian)(mian)的(de)水(shui)(shui)、塵土、泥沙挾卷(juan)(juan)(juan)(juan)而起(qi),其(qi)(qi)破(po)壞力(li)變動(dong)范圍很(hen)(hen)(hen)大(da),弱者僅能(neng)卷(juan)(juan)(juan)(juan)起(qi)稻(dao)草捆(kun)和(he)(he)(或)衣物(wu)(wu)強者可(ke)(ke)按樹倒屋,至把人、畜也(ye)一(yi)并升起(qi),經(jing)過水(shui)(shui)面(mian)(mian)時(shi)可(ke)(ke)吸水(shui)(shui)上升如柱,(這時(shi)稱水(shui)(shui)龍(long)(long)(long)卷(juan)(juan)(juan)(juan)),所以龍(long)(long)(long)卷(juan)(juan)(juan)(juan)風(feng)(feng)(feng)范圍雖小(xiao),但造(zao)(zao)成的(de)災(zai)情卻很(hen)(hen)(hen)嚴重。龍(long)(long)(long)卷(juan)(juan)(juan)(juan)風(feng)(feng)(feng)的(de)移(yi)(yi)向(xiang)、移(yi)(yi)速(su)是由其(qi)(qi)母云(yun)(產(chan)(chan)生龍(long)(long)(long)卷(juan)(juan)(juan)(juan)的(de)積雨云(yun))的(de)移(yi)(yi)動(dong)決(jue)定的(de),母云(yun)的(de)移(yi)(yi)速(su)通常(chang)為(wei)每小(xiao)時(shi)40-50公(gong)(gong)(gong)里(li)(li),最(zui)(zui)快可(ke)(ke)達(da)(da)90-100公(gong)(gong)(gong)里(li)(li)。其(qi)(qi)移(yi)(yi)動(dong)路徑(jing)多(duo)呈直(zhi)線,一(yi)般只(zhi)有(you)幾公(gong)(gong)(gong)里(li)(li),個別可(ke)(ke)達(da)(da)數十公(gong)(gong)(gong)里(li)(li)。龍(long)(long)(long)卷(juan)(juan)(juan)(juan)風(feng)(feng)(feng)是強對流(liu)天氣(qi)的(de)產(chan)(chan)物(wu)(wu),常(chang)發生于北緯(wei)20-50度地(di)(di)帶低(di)(di)層(ceng)大(da)氣(qi)層(ceng)結具有(you)很(hen)(hen)(hen)大(da)對流(liu)不(bu)穩定的(de)地(di)(di)區,往(wang)往(wang)與(yu)鋒面(mian)(mian)、氣(qi)旋(xuan)或非熱(re)帶性雷(lei)暴相伴(ban)隨。登(deng)陸(lu)后的(de)熱(re)帶氣(qi)旋(xuan)移(yi)(yi)到中緯(wei)趨向(xiang)衰亡時(shi),也(ye)很(hen)(hen)(hen)易(yi)出現龍(long)(long)(long)卷(juan)(juan)(juan)(juan)風(feng)(feng)(feng),有(you)時(shi)還可(ke)(ke)出現在熱(re)帶地(di)(di)區。根據龍(long)(long)(long)卷(juan)(juan)(juan)(juan)風(feng)(feng)(feng)產(chan)(chan)生的(de)地(di)(di)區可(ke)(ke)分(fen)為(wei)陸(lu)龍(long)(long)(long)卷(juan)(juan)(juan)(juan)(產(chan)(chan)生在陸(lu)地(di)(di)上空)和(he)(he)水(shui)(shui)龍(long)(long)(long)卷(juan)(juan)(juan)(juan)(產(chan)(chan)生在海面(mian)(mian)或水(shui)(shui)面(mian)(mian)上空)。龍(long)(long)(long)卷(juan)(juan)(juan)(juan)風(feng)(feng)(feng)很(hen)(hen)(hen)難(nan)預報,測(ce)雨雷(lei)達(da)(da)也(ye)未曾直(zhi)接觀(guan)測(ce)到過。
龍(long)卷風(feng),是一種(zhong)具有(you)一定破壞力(li)的自然現象。一般(ban)(ban)情況下,龍(long)卷風(feng)是一種(zhong)氣旋。它在(zai)接觸地面時(shi),直(zhi)徑從幾(ji)米到(dao)幾(ji)百米,平均為(wei)250米左右(you),最大(da)為(wei)1000米左右(you)。在(zai)空中(zhong)直(zhi)徑可(ke)有(you)幾(ji)千(qian)(qian)米,最大(da)有(you)10千(qian)(qian)米。極(ji)大(da)風(feng)速(su)每小時(shi)可(ke)達(da)150千(qian)(qian)米至450千(qian)(qian)米,龍(long)卷風(feng)持續(xu)時(shi)間(jian),一般(ban)(ban)僅(jin)幾(ji)分鐘,最長不過幾(ji)小時(shi)。所到(dao)之處萬物遭劫。龍(long)卷風(feng)漏斗(dou)狀中(zhong)心(xin)由吸起的塵土和凝聚的水氣組成可(ke)見的“龍(long)嘴”。在(zai)海(hai)洋上(shang),尤其是在(zai)熱帶(dai),類似的景象在(zai)發生(sheng)稱為(wei)海(hai)上(shang)龍(long)卷風(feng)。
龍(long)卷(juan)風通常是極(ji)其快速(su)的,每(mei)秒鐘100米(mi)的風速(su)不(bu)足為奇,甚至達(da)到(dao)每(mei)秒鐘175米(mi)以上,比12級臺風還要(yao)大五、六(liu)倍。風的范(fan)圍很小,一(yi)般直徑只(zhi)有25~100米(mi),只(zhi)在(zai)極(ji)少數的情況下直徑才達(da)到(dao)一(yi)公里以上;從發生到(dao)消失只(zhi)有幾分種(zhong),最多幾個小時。
大多數(shu)龍(long)卷風(feng)在(zai)北半球(qiu)是逆時針(zhen)旋轉(zhuan),在(zai)南(nan)半球(qiu)是順時針(zhen),也(ye)有例外情況。卷風(feng)形成的確切機理仍在(zai)研究中,一般認為是與大氣的劇烈活(huo)動有關。
從19世紀以來,天氣預報的準確性大大提高,氣象雷達能夠監測到龍(long)卷(juan)風、颶(ju)風等各種災害風暴。
龍卷風經過之處,常會(hui)發生拔起大樹、掀翻車(che)輛(liang)、摧(cui)毀建筑物(wu)等現象(xiang),它往(wang)往(wang)使成片莊(zhuang)稼、成萬株果木瞬間(jian)被毀,令交(jiao)通中(zhong)斷,房(fang)屋(wu)倒(dao)塌,人(ren)畜生命和經濟遭受損失(shi)。
龍(long)卷風這種自(zi)然(ran)現(xian)象是云層中(zhong)雷(lei)暴(bao)的(de)(de)產物(wu),具體的(de)(de)說,龍(long)卷風就是雷(lei)暴(bao)巨大(da)能量中(zhong)的(de)(de)一小(xiao)部分在很(hen)小(xiao)的(de)(de)區域(yu)內集中(zhong)釋放的(de)(de)一種形式(shi)。
龍卷風(feng)的形成可(ke)以(yi)分為四(si)個階段(duan):
(1)大氣的(de)(de)不穩(wen)定性產生強烈(lie)的(de)(de)上升氣流(liu),由(you)于急流(liu)中(zhong)的(de)(de)最大過(guo)境氣流(liu)的(de)(de)影響,它被進一步加強。
(2)由于與在垂(chui)直方(fang)向上速度和方(fang)向均有切變的風相(xiang)互作用,上升氣流在對流層的中部開(kai)始旋(xuan)轉(zhuan),形成中尺度氣旋(xuan)。
(3)隨(sui)著中尺度(du)氣(qi)旋(xuan)(xuan)向地面(mian)發(fa)展和向上(shang)伸(shen)展,它本身變細并(bing)增強(qiang)。同時,一個小面(mian)積(ji)的增強(qiang)輔合,即初生的龍卷在氣(qi)旋(xuan)(xuan)內部形成,產生氣(qi)旋(xuan)(xuan)的同樣過程,形成龍卷核(he)心。
(4)龍卷(juan)核(he)心中(zhong)的(de)(de)旋轉與(yu)氣旋中(zhong)的(de)(de)不同(tong),它(ta)的(de)(de)強度足以使龍卷(juan)一直伸(shen)展到(dao)地(di)面(mian)。當發展的(de)(de)渦旋到(dao)達地(di)面(mian)高度時,地(di)面(mian)氣壓(ya)急劇(ju)下降(jiang),地(di)面(mian)風(feng)速急劇(ju)上升,形(xing)成龍卷(juan)風(feng)。
龍(long)(long)(long)卷(juan)(juan)風(feng)發(fa)生至消散的(de)(de)(de)時間(jian)短,作用面積(ji)很(hen)小,以(yi)至于現有的(de)(de)(de)探測(ce)儀(yi)器(qi)沒(mei)有足夠的(de)(de)(de)靈敏度來對龍(long)(long)(long)卷(juan)(juan)風(feng)進行準確(que)的(de)(de)(de)觀(guan)測(ce)。相(xiang)對來說,多(duo)普勒(le)雷(lei)達(da)是比(bi)較有效和常用的(de)(de)(de)一種(zhong)觀(guan)測(ce)儀(yi)器(qi)。多(duo)普勒(le)雷(lei)達(da)對準龍(long)(long)(long)卷(juan)(juan)風(feng)發(fa)出的(de)(de)(de)微(wei)波束,微(wei)波信(xin)號(hao)(hao)被(bei)龍(long)(long)(long)卷(juan)(juan)風(feng)中的(de)(de)(de)碎屑(xie)和雨點反射(she)后重被(bei)雷(lei)達(da)接(jie)收。如(ru)果龍(long)(long)(long)卷(juan)(juan)風(feng)遠離雷(lei)達(da)而去,反射(she)回(hui)的(de)(de)(de)微(wei)波信(xin)號(hao)(hao)頻率將向(xiang)低頻方(fang)(fang)向(xiang)移(yi)動;反之,如(ru)果龍(long)(long)(long)卷(juan)(juan)風(feng)越來越接(jie)近雷(lei)達(da),則反射(she)回(hui)的(de)(de)(de)信(xin)號(hao)(hao)將向(xiang)高頻方(fang)(fang)向(xiang)移(yi)動。這種(zhong)現象(xiang)被(bei)稱為多(duo)普勒(le)頻移(yi)。接(jie)收到(dao)信(xin)號(hao)(hao)后,雷(lei)達(da)操作人員就可(ke)以(yi)通過分(fen)析頻移(yi)數(shu)據(ju),計算出龍(long)(long)(long)卷(juan)(juan)風(feng)的(de)(de)(de)速度和移(yi)動方(fang)(fang)向(xiang)。
雙極化技術的(de)(de)出現(xian)對多普勒天氣雷達(da)探(tan)測中氣旋和龍卷(juan)進行了(le)有力的(de)(de)補充,全面提升了(le)對龍卷(juan)微物理特(te)征(zheng)分(fen)析與預警(jing)預報水(shui)平。①由于多普勒天氣雷達(da)對較小(xiao)尺度的(de)(de)龍卷(juan)渦(wo)旋探(tan)測需要具有良好的(de)(de)空間分(fen)辨率,然而(er)(er)對雙極化探(tan)測而(er)(er)言并不需要太高的(de)(de)精(jing)度。②雙極化特(te)征(zheng)信號(hao)不同于多普勒特(te)征(zheng)信號(hao),由于其是“各(ge)向同性”的(de)(de),所以并不依賴于觀(guan)測角度的(de)(de)變化。③當龍卷(juan)在夜間發生或被大量降水(shui)包裹著難以通(tong)過多普勒雷達(da)觀(guan)測發現(xian)時,雙極化信息更能有效地(di)將其識別。
Wurman設計(ji)(ji)開(kai)發了第一(yi)部X波段(duan)移動(dong)式快速(su)掃描雷(lei)達(da)(da) Rapid DOW,該(gai)雷(lei)達(da)(da)每(mei)7秒可以完成一(yi)次360°的(de)體掃,在14秒的(de)時間里(li)可以探測到 12個波束范(fan)圍的(de)數據,并且其距離分辨率達(da)(da)到11米,更易于對龍卷三維結構進(jin)行研究。從(cong)當前(qian)對龍卷的(de)探測技術來看,快速(su)掃描雷(lei)達(da)(da)在時空(kong)尺度上(shang)對龍卷觀(guan)測獨特優勢(shi)。而美國計(ji)(ji)劃的(de)下一(yi)代天氣雷(lei)達(da)(da)網絡(luo)也定位(wei)為多功能(neng)相控陣雷(lei)達(da)(da)。所以可見該(gai)技術未來必將成為研究該(gai)類天氣的(de)主要手段(duan)。
多(duo)漩(xuan)渦(wo)(wo)龍(long)卷風(feng)(Multiple vortex)指帶有兩股以上圍繞同(tong)一個中心旋轉的(de)漩(xuan)渦(wo)(wo)的(de)龍(long)卷風(feng)。多(duo)漩(xuan)渦(wo)(wo)結構經常出(chu)現在劇烈的(de)龍(long)卷風(feng)上,并且(qie)這些小漩(xuan)渦(wo)(wo)在主龍(long)卷風(feng)經過的(de)地區上往往會造成更大的(de)破壞(huai)。
水(shui)(shui)龍(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(或(huo)稱(cheng)海(hai)龍(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan),英(ying)文:waterspout)可(ke)以簡單地(di)(di)定義(yi)為(wei)水(shui)(shui)上(shang)的(de)龍(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)風,通(tong)常意思是在(zai)(zai)(zai)水(shui)(shui)上(shang)的(de)非超級單體(ti)龍(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)風。世界各地(di)(di)的(de)海(hai)洋和湖泊等都可(ke)能(neng)(neng)出(chu)(chu)現(xian)水(shui)(shui)龍(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)。在(zai)(zai)(zai)美(mei)(mei)國,水(shui)(shui)龍(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)通(tong)常發生在(zai)(zai)(zai)美(mei)(mei)國東南部海(hai)岸,尤其(qi)在(zai)(zai)(zai)佛(fo)羅(luo)里達南部和墨西哥(ge)灣。水(shui)(shui)龍(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)雖在(zai)(zai)(zai)定義(yi)上(shang)是龍(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)風的(de)一種(zhong),不過(guo)其(qi)破壞(huai)性要比最(zui)強(qiang)大的(de)大草原龍(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)風小,但是它們仍然是相當(dang)危險的(de)。水(shui)(shui)龍(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)能(neng)(neng)吹(chui)翻小船,毀壞(huai)船只,當(dang)吹(chui)襲陸地(di)(di)時就有(you)更(geng)大的(de)破壞(huai),并奪去生命。當(dang)水(shui)(shui)龍(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)很可(ke)能(neng)(neng)產生或(huo)在(zai)(zai)(zai)海(hai)岸水(shui)(shui)域上(shang)已經看得見的(de)時候,美(mei)(mei)國國家(jia)氣(qi)象局(ju)將會經常發出(chu)(chu)特殊的(de)海(hai)上(shang)警告(gao),或(huo)者當(dang)水(shui)(shui)龍(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)會向陸地(di)(di)移動時發出(chu)(chu)龍(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)風警告(gao)。
陸龍(long)(long)卷(juan)(juan)(英(ying)文(wen):landspout,美國國家氣(qi)象局(ju)稱dust-tube tornado)用以(yi)描述一(yi)種和(he)(he)中尺度(du)氣(qi)旋沒有關聯(lian)的龍(long)(long)卷(juan)(juan)風。陸龍(long)(long)卷(juan)(juan)和(he)(he)水龍(long)(long)卷(juan)(juan)有一(yi)些相同的特(te)點,例如強度(du)相對較弱(ruo)(ruo)、持續時間短、冷凝形(xing)成(cheng)的漏斗云較小且經常不接觸(chu)地面(mian)等。雖然強度(du)相對較弱(ruo)(ruo),但陸龍(long)(long)卷(juan)(juan)依然會帶來強風和(he)(he)嚴重破壞。
火(huo)(huo)(huo)(huo)龍卷(juan)(juan)(juan),非常罕(han)見(jian)的(de)(de)(de)龍卷(juan)(juan)(juan)風形態,由(you)陸龍卷(juan)(juan)(juan)與火(huo)(huo)(huo)(huo)焰(yan)(yan)的(de)(de)(de)結合(he)。2010年,位于南半球的(de)(de)(de)巴西遭遇罕(han)見(jian)的(de)(de)(de)干旱少雨天氣,全國多地燃起(qi)(qi)了(le)山火(huo)(huo)(huo)(huo)。8月24日(ri),巴西圣保羅市一(yi)處(chu)火(huo)(huo)(huo)(huo)點刮起(qi)(qi)了(le)龍卷(juan)(juan)(juan)風,形成了(le)罕(han)見(jian)的(de)(de)(de)火(huo)(huo)(huo)(huo)焰(yan)(yan)龍卷(juan)(juan)(juan)風景觀。龍卷(juan)(juan)(juan)風夾起(qi)(qi)火(huo)(huo)(huo)(huo)焰(yan)(yan)高達數米,像一(yi)條(tiao)巨大的(de)(de)(de)火(huo)(huo)(huo)(huo)龍旋(xuan)轉前進(jin)。這條(tiao)“火(huo)(huo)(huo)(huo)龍風”于24日(ri)被拍攝(she)到。“火(huo)(huo)(huo)(huo)龍”在燃燒的(de)(de)(de)田(tian)野(ye)上(shang)飛舞高約數米高,阻斷了(le)一(yi)條(tiao)公路(lu)。為了(le)熄(xi)滅這條(tiao)“火(huo)(huo)(huo)(huo)龍”,當地出動了(le)直升機(ji)。
出現(xian)“火龍風”的(de)(de)地區(qu)已經有3個月沒(mei)有下雨。異常干旱的(de)(de)天氣和強勁的(de)(de)風勢(shi)助長了(le)此處的(de)(de)火勢(shi)。巴西(xi)全(quan)球電視臺(tai)報道(dao)稱,圣保羅(luo)地區(qu)的(de)(de)空(kong)氣干燥程度已趕上了(le)撒哈拉沙漠(mo)。
龍卷(juan)風按它的破(po)壞(huai)程度不同,分為(wei)0-5增強藤田級(ji)(ji)數,簡單來說就稱為(wei)EF級(ji)(ji),由1971年芝加(jia)哥大(da)學的藤田哲也博(bo)士(shi)所提(ti)出。
EF0級:風(feng)速在65-85英里(li)每小(xiao)時,約合105-137公里(li)每小(xiao)時,雖然較弱,但還是足以把樹枝吹(chui)斷,把較輕的(de)碎(sui)片(pian)卷起來擊碎(sui)玻璃,一些煙囪會(hui)被吹(chui)斷。(出(chu)現幾(ji)率極高,53.5%)
EF1級:風速在每(mei)小時86-110英里(li)每(mei)小時,約合138-177公(gong)里(li)每(mei)小時,它(ta)們可以(yi)把屋頂吹(chui)走(zou),把活(huo)動板房(fang)給吹(chui)翻,一(yi)些較輕的汽車會被吹(chui)翻或刮離路面。(出現幾率較高,31.6%)
EF2級:風速在111-135英里(li)每小(xiao)時,約合178-217公里(li)每小(xiao)時,它們可(ke)以把沉重(zhong)的甘草包吹(chui)出去幾百米遠,把一(yi)棵(ke)大樹連根拔起,貨車可(ke)以刮離路面。(出現幾率中(zhong)等偏低,10.7%)
EF3級:風速在(zai)136-165英(ying)里(li)每(mei)小時,約合218-266公里(li)每(mei)小時,它們可以把(ba)一(yi)輛較(jiao)重汽車吹翻,樹木被吹離(li)地(di)面,房屋一(yi)大半被毀,火(huo)車脫(tuo)離(li)軌道。(出現(xian)幾率(lv)低,3.4%)
EF4級:風速(su)在166-200英里每(mei)小時,約合267-322公里每(mei)小時,它(ta)們(men)可(ke)以把(ba)一輛汽(qi)車刮飛(fei),把(ba)一幢牢固的房屋夷為平地,樹木(mu)被刮到幾(ji)百(bai)米高空。(出現幾(ji)率很低,0.7%)
EF5級:EF5級風速超(chao)過每小時200英里每小時,也(ye)就是超(chao)過了322公里每小時,房屋完全吹毀(hui),汽車(che)完全刮飛,路面(mian)上的瀝青(qing)也(ye)會(hui)被刮走,貨車(che)、火車(che)、列(lie)車(che)全部脫離地(di)面(mian)。(出現幾(ji)率較低偏(pian)高(gao),20%—45%)
龍卷風(feng)(feng)并沒有(you)EF6級(ji)。那是(shi)絕對不可能(neng)的(de)(de)(de),這是(shi)根(gen)據物理和氣象(xiang)學推算出來的(de)(de)(de),所以,1999年5月3日俄克拉(la)荷(he)馬城的(de)(de)(de)龍卷風(feng)(feng)不是(shi)EF6級(ji),而(er)是(shi)EF5級(ji),但是(shi)電視臺也(ye)報(bao)道過(guo)(guo)當天超過(guo)(guo)每小時512公里的(de)(de)(de)風(feng)(feng)速(su),而(er)且在一個雷達上估(gu)測到了(le)318英里每小時的(de)(de)(de)大風(feng)(feng),這就表明龍卷風(feng)(feng)的(de)(de)(de)破壞力量很大,不要(yao)相信有(you)EF6級(ji)龍卷風(feng)(feng),那是(shi)虛構。
除(chu)此之外,龍(long)卷風還可(ke)以分為4個(ge)形狀:
煙囪龍卷風:輪廓直,比較粗壯,強度中等,一般在EF2—EF4級左右。
繩形龍卷風:纖(xian)細,輪(lun)廓教彎,強度弱,一般在EF0—EF2左右。
楔(xie)形(xing)龍卷風:長度(du)(du)較寬(kuan),可達1.5公里,寬(kuan)度(du)(du)超過(guo)高度(du)(du),強(qiang)度(du)(du)強(qiang),一般在EF4—EF5左右。
雙胞胎龍(long)卷(juan)風:兩個龍(long)卷(juan)風,有(you)的粗,有(you)的細,強度不定。
全(quan)(quan)球除(chu)南(nan)極洲(zhou)以外(wai)的(de)大洲(zhou)都(dou)有龍(long)卷(juan)(juan)(juan)風(feng)記錄,龍(long)卷(juan)(juan)(juan)風(feng)主要發(fa)生在中緯度地區,其中美國(guo)發(fa)生最為(wei)頻繁(fan),堪稱“龍(long)卷(juan)(juan)(juan)王(wang)國(guo)”,被稱為(wei)“龍(long)卷(juan)(juan)(juan)風(feng)之鄉(xiang)”,其發(fa)生的(de)龍(long)卷(juan)(juan)(juan)風(feng)約占全(quan)(quan)球龍(long)卷(juan)(juan)(juan)風(feng)總(zong)數的(de)75%;其次(ci)為(wei)加拿大;歐洲(zhou)西部和中部、中國(guo)、孟(meng)加拉國(guo)、日本(ben)、澳大利亞、新西蘭、南(nan)非和阿根廷等國(guo)家或地區龍(long)卷(juan)(juan)(juan)風(feng)發(fa)生也(ye)較為(wei)頻繁(fan)。
年(nian)(nian)(nian)(nian)尺(chi)度特征美國(guo)(guo)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)每(mei)年(nian)(nian)(nian)(nian)有(you)(you)1000多個(ge)(1991—2010年(nian)(nian)(nian)(nian)間,平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)為(wei)1253個(ge)/年(nian)(nian)(nian)(nian))。其(qi)(qi)次(ci)為(wei)加(jia)拿(na)大(da)(da),記錄到的(de)(de)(de)(de)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)約(yue)70個(ge)/年(nian)(nian)(nian)(nian),估計實(shi)際發(fa)生的(de)(de)(de)(de)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)約(yue)150個(ge)/年(nian)(nian)(nian)(nian)。歐洲平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)觀(guan)測到的(de)(de)(de)(de)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風大(da)(da)約(yue)有(you)(you)330個(ge)/年(nian)(nian)(nian)(nian),其(qi)(qi)中陸(lu)(lu)(lu)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)170個(ge),水(shui)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)160個(ge),而實(shi)際發(fa)生的(de)(de)(de)(de)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風大(da)(da)約(yue)有(you)(you)700個(ge)/年(nian)(nian)(nian)(nian),其(qi)(qi)中陸(lu)(lu)(lu)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)300個(ge),水(shui)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)390個(ge)。歐洲龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風多發(fa)生于英國(guo)(guo)、德國(guo)(guo)、法國(guo)(guo)和西班牙:英國(guo)(guo)(1981—2010年(nian)(nian)(nian)(nian)間)平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)每(mei)年(nian)(nian)(nian)(nian)大(da)(da)約(yue)有(you)(you) (47.2±10.5)個(ge)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風,其(qi)(qi)中陸(lu)(lu)(lu)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(36.5±10.1)個(ge),水(shui)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(12.7±2.8)個(ge);法國(guo)(guo)平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)每(mei)年(nian)(nian)(nian)(nian)有(you)(you)15~20個(ge)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風。亞洲的(de)(de)(de)(de)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風主要(yao)發(fa)生在(zai)中國(guo)(guo)、日(ri)(ri)本、印度和孟加(jia)拉國(guo)(guo):中國(guo)(guo)平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)每(mei)年(nian)(nian)(nian)(nian)發(fa)生的(de)(de)(de)(de)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風有(you)(you)73個(ge);日(ri)(ri)本平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)每(mei)年(nian)(nian)(nian)(nian)發(fa)生20.5個(ge)陸(lu)(lu)(lu)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)和4.5個(ge)水(shui)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan);孟加(jia)拉國(guo)(guo)平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)每(mei)年(nian)(nian)(nian)(nian)發(fa)生的(de)(de)(de)(de)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風有(you)(you)2個(ge)。大(da)(da)洋洲的(de)(de)(de)(de)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風主要(yao)發(fa)生在(zai)澳大(da)(da)利(li)(li)亞和新西蘭:澳大(da)(da)利(li)(li)亞平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)每(mei)年(nian)(nian)(nian)(nian)發(fa)生的(de)(de)(de)(de)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風有(you)(you)29個(ge),新西蘭平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)每(mei)年(nian)(nian)(nian)(nian)發(fa)生的(de)(de)(de)(de)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風有(you)(you)17個(ge)。南美洲的(de)(de)(de)(de)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風多發(fa)于阿根(gen)廷中部(bu)的(de)(de)(de)(de)潘(pan)帕斯草原(yuan):阿根(gen)廷平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)每(mei)年(nian)(nian)(nian)(nian)記錄到的(de)(de)(de)(de)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風大(da)(da)概有(you)(you)10個(ge);巴西、智利(li)(li)和烏拉圭也(ye)有(you)(you)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風的(de)(de)(de)(de)記錄,巴西平(ping)(ping)(ping)均(jun)(jun)(jun)(jun)每(mei)年(nian)(nian)(nian)(nian)記錄到的(de)(de)(de)(de)龍(long)(long)(long)(long)(long)(long)(long)卷(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)(juan)風有(you)(you)3個(ge)。
美(mei)國的(de)龍(long)卷風(feng)多(duo)(duo)發(fa)(fa)(fa)于春(chun)季(ji),其(qi)次為夏季(ji),冬季(ji)最(zui)少發(fa)(fa)(fa)生(sheng)(sheng)。歐洲的(de)龍(long)卷風(feng)主要(yao)發(fa)(fa)(fa)生(sheng)(sheng)在夏季(ji),其(qi)次為秋(qiu)季(ji):英國龍(long)卷風(feng)主要(yao)發(fa)(fa)(fa)生(sheng)(sheng)在秋(qiu)季(ji)(9—11月(yue)(yue)),其(qi)次為夏季(ji)(6—8月(yue)(yue)),11月(yue)(yue)為龍(long)卷風(feng)發(fa)(fa)(fa)生(sheng)(sheng)最(zui)多(duo)(duo)月(yue)(yue);德國2/3的(de)龍(long)卷風(feng)發(fa)(fa)(fa)生(sheng)(sheng)在6—8月(yue)(yue),其(qi)中(zhong)7月(yue)(yue)龍(long)卷風(feng)發(fa)(fa)(fa)生(sheng)(sheng)頻率達27%;法國的(de)龍(long)卷風(feng)多(duo)(duo)發(fa)(fa)(fa)于春(chun)季(ji)和夏季(ji),8月(yue)(yue)發(fa)(fa)(fa)生(sheng)(sheng)最(zui)多(duo)(duo);西(xi)班牙的(de)龍(long)卷風(feng)多(duo)(duo)發(fa)(fa)(fa)于暖季(ji),明顯的(de)趨向(xiang)于秋(qiu)季(ji)。澳大利(li)亞的(de)龍(long)卷風(feng)多(duo)(duo)發(fa)(fa)(fa)于初(chu)春(chun)和夏季(ji),其(qi)次為初(chu)冬。中(zhong)國龍(long)卷風(feng)發(fa)(fa)(fa)生(sheng)(sheng)的(de)季(ji)節變(bian)化特征明顯,主要(yao)集中(zhong)在春(chun)夏兩季(ji),尤(you)以7月(yue)(yue)和8月(yue)(yue)最(zui)多(duo)(duo),兩月(yue)(yue)約占全年總數(shu)的(de)50%以上(shang)。日本56%的(de)陸龍(long)卷發(fa)(fa)(fa)生(sheng)(sheng)在7—10月(yue)(yue),其(qi)中(zhong)9月(yue)(yue)最(zui)為頻繁,3月(yue)(yue)最(zui)少;水龍(long)卷主要(yao)發(fa)(fa)(fa)生(sheng)(sheng)在9—10月(yue)(yue),10月(yue)(yue)最(zui)多(duo)(duo)。
美國(guo)的(de)(de)(de)佛羅里達(da)州(zhou)(zhou)和(he)(he)(he)中南(nan)(nan)(nan)部(bu)(bu)(bu)(bu)平(ping)原(yuan)是龍(long)(long)(long)(long)卷(juan)(juan)(juan)風(feng)的(de)(de)(de)高(gao)發(fa)(fa)區(qu)(qu)(qu),中南(nan)(nan)(nan)部(bu)(bu)(bu)(bu)平(ping)原(yuan)稱為“龍(long)(long)(long)(long)卷(juan)(juan)(juan)走廊(lang)”,其(qi)范圍一(yi)般(ban)(ban)指從德克(ke)薩斯州(zhou)(zhou)中部(bu)(bu)(bu)(bu)向北(bei)到愛(ai)荷華州(zhou)(zhou)北(bei)部(bu)(bu)(bu)(bu),以及(ji)從堪薩斯州(zhou)(zhou)中部(bu)(bu)(bu)(bu)和(he)(he)(he)內布(bu)拉斯加(jia)東部(bu)(bu)(bu)(bu)到俄(e)亥俄(e)西(xi)(xi)(xi)部(bu)(bu)(bu)(bu)的(de)(de)(de)區(qu)(qu)(qu)域(yu)(yu)。英(ying)國(guo)的(de)(de)(de)龍(long)(long)(long)(long)卷(juan)(juan)(juan)主(zhu)要(yao)發(fa)(fa)生(sheng)于(yu)(yu)(yu)英(ying)格蘭(lan)(lan)的(de)(de)(de)東部(bu)(bu)(bu)(bu)和(he)(he)(he)南(nan)(nan)(nan)部(bu)(bu)(bu)(bu)以及(ji)海(hai)峽群島周(zhou)邊。德國(guo)的(de)(de)(de)龍(long)(long)(long)(long)卷(juan)(juan)(juan)風(feng)多(duo)發(fa)(fa)于(yu)(yu)(yu)沿海(hai)和(he)(he)(he)丘陵地(di)(di)區(qu)(qu)(qu)。法(fa)國(guo)的(de)(de)(de)龍(long)(long)(long)(long)卷(juan)(juan)(juan)風(feng)多(duo)發(fa)(fa)于(yu)(yu)(yu)西(xi)(xi)(xi)北(bei)部(bu)(bu)(bu)(bu)、南(nan)(nan)(nan)部(bu)(bu)(bu)(bu)和(he)(he)(he)東部(bu)(bu)(bu)(bu)。西(xi)(xi)(xi)班(ban)牙(ya)的(de)(de)(de)龍(long)(long)(long)(long)卷(juan)(juan)(juan)風(feng)多(duo)發(fa)(fa)于(yu)(yu)(yu)地(di)(di)中海(hai)區(qu)(qu)(qu)域(yu)(yu)和(he)(he)(he)加(jia)的(de)(de)(de)斯灣(wan)附近省(sheng)(sheng)(sheng)(sheng)份(fen)。中國(guo)龍(long)(long)(long)(long)卷(juan)(juan)(juan)風(feng)一(yi)般(ban)(ban)多(duo)發(fa)(fa)生(sheng)在中東部(bu)(bu)(bu)(bu)地(di)(di)形相(xiang)對平(ping)坦的(de)(de)(de)平(ping)原(yuan)地(di)(di)區(qu)(qu)(qu),平(ping)原(yuan)多(duo)于(yu)(yu)(yu)山區(qu)(qu)(qu);從區(qu)(qu)(qu)域(yu)(yu)尺度(du)來看(kan),長江(jiang)三角洲(zhou)、蘇(su)北(bei)、魯西(xi)(xi)(xi)南(nan)(nan)(nan)、豫東等平(ping)原(yuan)、湖(hu)沼區(qu)(qu)(qu)以及(ji)雷(lei)州(zhou)(zhou)半(ban)島等地(di)(di)都是龍(long)(long)(long)(long)卷(juan)(juan)(juan)風(feng)的(de)(de)(de)易發(fa)(fa)區(qu)(qu)(qu);從省(sheng)(sheng)(sheng)(sheng)級行政單(dan)元尺度(du)來看(kan),江(jiang)蘇(su)省(sheng)(sheng)(sheng)(sheng)、安徽(hui)省(sheng)(sheng)(sheng)(sheng)、廣東省(sheng)(sheng)(sheng)(sheng)、河南(nan)(nan)(nan)省(sheng)(sheng)(sheng)(sheng)、湖(hu)北(bei)省(sheng)(sheng)(sheng)(sheng)是龍(long)(long)(long)(long)卷(juan)(juan)(juan)風(feng)多(duo)發(fa)(fa)的(de)(de)(de)省(sheng)(sheng)(sheng)(sheng)份(fen),黑龍(long)(long)(long)(long)江(jiang)省(sheng)(sheng)(sheng)(sheng)、河北(bei)省(sheng)(sheng)(sheng)(sheng)、浙江(jiang)省(sheng)(sheng)(sheng)(sheng)、江(jiang)西(xi)(xi)(xi)省(sheng)(sheng)(sheng)(sheng)和(he)(he)(he)湖(hu)南(nan)(nan)(nan)省(sheng)(sheng)(sheng)(sheng)等省(sheng)(sheng)(sheng)(sheng)份(fen)龍(long)(long)(long)(long)卷(juan)(juan)(juan)風(feng)的(de)(de)(de)發(fa)(fa)生(sheng)頻(pin)次較高(gao)。1961—1993年間(jian)日本(ben)的(de)(de)(de)陸龍(long)(long)(long)(long)卷(juan)(juan)(juan)和(he)(he)(he)水龍(long)(long)(long)(long)卷(juan)(juan)(juan)主(zhu)要(yao)發(fa)(fa)生(sheng)在沿海(hai)地(di)(di)區(qu)(qu)(qu),而(er)關東地(di)(di)區(qu)(qu)(qu)大量龍(long)(long)(long)(long)卷(juan)(juan)(juan)風(feng)遠離沿海(hai)區(qu)(qu)(qu)域(yu)(yu)。大洋洲(zhou)的(de)(de)(de)龍(long)(long)(long)(long)卷(juan)(juan)(juan)風(feng)主(zhu)要(yao)發(fa)(fa)生(sheng)在澳大利(li)亞和(he)(he)(he)新西(xi)(xi)(xi)蘭(lan)(lan)。澳大利(li)亞的(de)(de)(de)龍(long)(long)(long)(long)卷(juan)(juan)(juan)風(feng)主(zhu)要(yao)發(fa)(fa)生(sheng)于(yu)(yu)(yu)東南(nan)(nan)(nan)部(bu)(bu)(bu)(bu)和(he)(he)(he)西(xi)(xi)(xi)南(nan)(nan)(nan)部(bu)(bu)(bu)(bu)。南(nan)(nan)(nan)美洲(zhou)的(de)(de)(de)龍(long)(long)(long)(long)卷(juan)(juan)(juan)風(feng)多(duo)發(fa)(fa)于(yu)(yu)(yu)阿根廷中部(bu)(bu)(bu)(bu)的(de)(de)(de)潘帕斯草(cao)原(yuan)。巴西(xi)(xi)(xi)龍(long)(long)(long)(long)卷(juan)(juan)(juan)多(duo)發(fa)(fa)于(yu)(yu)(yu)南(nan)(nan)(nan)部(bu)(bu)(bu)(bu)和(he)(he)(he)東南(nan)(nan)(nan)部(bu)(bu)(bu)(bu)。
我國大(da)部(bu)分(fen)省(sheng)(區、市)都有(you)龍(long)卷(juan)(juan)(juan)風的(de)蹤(zong)跡,主(zhu)要發生在我國東(dong)部(bu)平(ping)原地(di)區,1991年(nian)-2014年(nian),我國平(ping)均(jun)每(mei)年(nian)有(you)43個(ge)龍(long)卷(juan)(juan)(juan)風,其中(zhong)江蘇和廣東(dong)最多(duo),年(nian)均(jun)龍(long)卷(juan)(juan)(juan)風分(fen)別為5.5個(ge)和4.8個(ge)。春季(ji)、夏季(ji)是(shi)龍(long)卷(juan)(juan)(juan)風的(de)多(duo)發季(ji)節,4-8月龍(long)卷(juan)(juan)(juan)風占全年(nian)的(de)92%。
龍(long)(long)卷(juan)風是一(yi)種破(po)壞力極強的小(xiao)尺度(du)天氣現(xian)象,直徑(jing)一(yi)般(ban)在100米(mi)以(yi)下,強龍(long)(long)卷(juan)可達幾百米(mi)到1千米(mi)左右。相(xiang)比(bi)于(yu)臺風、副高這(zhe)些(xie)天氣系統中的“大塊頭(tou)”,龍(long)(long)卷(juan)風絕對屬(shu)于(yu)“小(xiao)個子”。而當前我(wo)們的氣象臺站不夠密集,以(yi)至(zhi)于(yu)龍(long)(long)卷(juan)風經常躲過氣象監測的“法眼(yan)”。
龍卷(juan)風強對流(liu)天氣往(wang)往(wang)生(sheng)(sheng)成(cheng)很(hen)突然,對某(mou)一地區的影響(xiang)時間也(ye)相對較短,“生(sheng)(sheng)命史(shi)”只(zhi)有十幾分(fen)鐘到個把小時。因此(ci),要(yao)提(ti)前(qian)24小時或(huo)是48小時預(yu)報(bao)局部地區的強對流(liu)天氣也(ye)就非常困(kun)難了。
龍卷風等強對流天氣的(de)生成和發展需要衡(heng)量綜(zong)合大(da)氣條(tiao)件,而(er)這(zhe)些條(tiao)件往往是難(nan)以預(yu)料、不確切的(de),再(zai)加(jia)上不同地區之間各不相同的(de)地形(xing)因素,也進一步(bu)增加(jia)了(le)準確監測(ce)、預(yu)報的(de)難(nan)度。
(1)龍(long)卷(juan)(juan)風發(fa)(fa)生(sheng)是(shi)(shi)(shi)和強烈(lie)發(fa)(fa)展的(de)(de)(de)(de)積雨云(yun)聯系在(zai)(zai)一起(qi)的(de)(de)(de)(de),也就(jiu)(jiu)是(shi)(shi)(shi)通常所說的(de)(de)(de)(de)雷雨云(yun)。龍(long)卷(juan)(juan)風出(chu)現(xian)(xian)時天空往往烏(wu)天黑地(云(yun)層低而深(shen)厚、亮(liang)度差(cha))、電閃(shan)雷鳴、風雨交加。以春未到秋(qiu)初最(zui)常見,在(zai)(zai)一天中以下(xia)午至傍晚和凌晨(chen)至早晨(chen)出(chu)現(xian)(xian)最(zui)多。當(dang)看到天空有類似的(de)(de)(de)(de)癥兆就(jiu)(jiu)要(yao)引起(qi)注(zhu)意。人群應立刻(ke)離開(kai)危(wei)險房(fang)屋(wu)、活動(dong)場(chang)所或其他簡(jian)易臨時住處,到附近比較堅固的(de)(de)(de)(de)房(fang)屋(wu)內躲(duo)(duo)避。在(zai)(zai)公共場(chang)所,要(yao)服從指揮,有秩序地向(xiang)指定(ding)地點疏散。躲(duo)(duo)避龍(long)卷(juan)(juan)風最(zui)為安全(quan)的(de)(de)(de)(de)地方是(shi)(shi)(shi)位于地下(xia)的(de)(de)(de)(de)空間或場(chang)所(如地下(xia)室或半地下(xia)室),地面上所有建筑物此時都不是(shi)(shi)(shi)安全(quan)躲(duo)(duo)避的(de)(de)(de)(de)場(chang)所。
(2)在野外遇到(dao)龍卷(juan)(juan)風襲擊時(shi),不必驚慌失措,應迅(xun)速朝龍卷(juan)(juan)風移動方向的(de)垂直(zhi)方向跑動,伏于(yu)低洼地面、溝渠等(deng),但要遠離(li)大樹、電(dian)線(xian)桿、廣告牌、圍墻等(deng),以免被砸(za)、被壓(ya)或發生觸(chu)電(dian)事故。如在汽(qi)車中(zhong),應及時(shi)離(li)開,到(dao)低洼地躲避,因(yin)為汽(qi)車本身沒有防御(yu)龍卷(juan)(juan)風能力(li),一(yi)旦(dan)汽(qi)車和人同時(shi)被龍卷(juan)(juan)風卷(juan)(juan)起,危害更(geng)大。
(3)在(zai)家遇到龍(long)(long)卷(juan)風時,遠離和(he)龍(long)(long)卷(juan)風同方向(xiang)(xiang)的(de)窗、門、房屋的(de)外圍墻壁,盡可能在(zai)龍(long)(long)卷(juan)風相反方向(xiang)(xiang)角落或比(bi)較(jiao)堅固的(de)小(xiao)房間抱頭蹲下,保護好(hao)自己的(de)頭部。在(zai)樓上,特別是農村的(de)樓房內(nei),應立即暫避到一樓比(bi)較(jiao)堅固的(de)桌子底下或廁(ce)所、儲物間內(nei)。這(zhe)是因(yin)為龍(long)(long)卷(juan)風中(zhong)心的(de)氣(qi)壓極低,容易被龍(long)(long)卷(juan)風外吸(xi)、房屋倒塌而殃及室內(nei)人員安全。
(4)在遭遇(yu)龍(long)卷(juan)風和(he)發(fa)生房屋倒塌、電桿折斷的情(qing)況下(xia),應及時(shi)切斷電源,以防觸電和(he)引發(fa)火(huo)災事故。如果是化(hua)工生產企業遭受龍(long)卷(juan)風襲擊,應及時(shi)關閉(bi)有(you)毒化(hua)學物品(pin)閥門,控制化(hua)學物品(pin)泄漏(lou),防止污染源向土(tu)壤和(he)水面(mian)擴散(san),必(bi)要時(shi)組(zu)織(zhi)附近市(shi)(村)民緊急轉移(yi)。
(5)龍(long)卷(juan)風(feng)后自(zi)(zi)救(jiu)(jiu)互(hu)救(jiu)(jiu)。由于(yu)龍(long)卷(juan)風(feng)的(de)(de)(de)(de)風(feng)力特(te)別(bie)(bie)大(da),具有巨大(da)的(de)(de)(de)(de)破壞(huai)作用,龍(long)卷(juan)經(jing)過的(de)(de)(de)(de)區域內,房屋等(deng)建筑物常會(hui)遭受不同程度的(de)(de)(de)(de)破壞(huai),甚至發生倒塌。因此,受龍(long)卷(juan)影響地區的(de)(de)(de)(de)群眾,尤(you)其是(shi)家庭、鄰里(li)之間在災(zai)后第一(yi)時(shi)間的(de)(de)(de)(de)自(zi)(zi)救(jiu)(jiu)互(hu)救(jiu)(jiu)可最大(da)限度減少(shao)(shao)人(ren)(ren)員(yuan)傷(shang)亡。被(bei)埋壓人(ren)(ren)員(yuan)要(yao)保(bao)持(chi)(chi)清醒頭腦,盡快(kuai)想法(fa)脫(tuo)離(li)險(xian)境,如果不能(neng)自(zi)(zi)我脫(tuo)險(xian)時(shi),應(ying)盡量(liang)創造和擴大(da)安全生存空間,減少(shao)(shao)對(dui)身體的(de)(de)(de)(de)擠壓,特(te)別(bie)(bie)是(shi)對(dui)腹部(bu)以(yi)上身體部(bu)位(wei)的(de)(de)(de)(de)壓物要(yao)清除或(huo)移(yi)開,加強對(dui)頭部(bu)及口(kou)、鼻等(deng)器官(guan)的(de)(de)(de)(de)自(zi)(zi)我保(bao)護,等(deng)待(dai)救(jiu)(jiu)援。救(jiu)(jiu)援時(shi)要(yao)講究方法(fa),首先(xian)應(ying)使被(bei)救(jiu)(jiu)者暴露頭部(bu),保(bao)持(chi)(chi)呼吸暢通,如有窒息,應(ying)立即進(jin)行人(ren)(ren)工呼吸。其次不可生拉(la)硬扯或(huo)使用利器硬挖被(bei)埋者,以(yi)免造成(cheng)進(jin)一(yi)步的(de)(de)(de)(de)損傷(shang),同時(shi)對(dui)傷(shang)重者及時(shi)送醫(yi)院搶救(jiu)(jiu)。